Aim: To compare the in-vitro elution characteristics of CMW1 and Palacos R bone cements containing gentamicin or teicoplanin or a combination of both.

Materials & Methods: Four types of bone cement discs (28x22mm) were prepared.

Disc 1(control) contained Palacos R or CMW1 cement without any added antibiotic.

The discs containing teicoplanin were prepared by adding teicoplanin powder (2gm) to the respective cement powder (40 gm with or without 0.5gm of gentamicin) and then adding the monomer (vacuum mixing).

All the discs were immersed in 50 ml normal saline bath in a sterile pot and maintained at temperature of 37 deg Celsius. 24 hours later a 5ml sample was taken from each pot for assay, to measure the amount of antibiotic eluted, using fluorescence polarization immuno-assay technique. The discs were then removed from the pots, washed with normal saline and reimmersed in a fresh 50 ml saline pot. This procedure was repeated at hours 48, 72, 120 and week 1, 2, 3 & 6 for all discs.

Results: All discs and assays were done in triplicate and average total value at 6 weeks (μ gm/ml) taken for statistical analysis.

CMW1:

Gentamicin eluted from disc4 was higher than disc2 (94.9 v 34.37. p< 0.0003).

PALACOS R:

Gentamicin eluted from disc4 was higher than disc2 (144.17 v 86.43. p< 0.0004).

Conclusion: Palacos R cement elutes more antibiotic than CMW1 and antibiotic combination in bone cement resulted in, mostly, synergistic effect of increased elution of individual antibiotic.